Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment 

Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.

▶ Fibroblast Infiltration and Proliferation in hADMs

Yang, Ho Jik, et al. "Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment." Bioengineering 11.4 (2024): 359.
 

Vacuum Plasma Treatment Device for Enhancing Fibroblast Activity on Machined and Rough Titanium Surfaces 

This study was conducted to compare the effects of an innovative plasma surface treatment device that does not need a gas supply for titanium disks with two different surface topographies: the prototypical machined surface (MAC) and one of the most diffused roughened ones (SL) obtained through grit blasting and acid etching. A total of 200-MAC and 200-SL titanium disks were used. Each group of disks was divided into four sub-groups of 40 samples each that were subjected to five different tests. Among these, 150-MAC and 150-SL were considered the test group, and they were treated with plasma for 15, 30, and 60 s after being removed from the sterile packaging. On the other hand, 50-MAC and 50-SL were considered the control group, and they were only removed from sterile plastic vials. The samples were analyzed to evaluate the capability of the plasma treatment in influencing protein adsorption, cell adhesion, proliferation, and microbial growth on the test group disks when compared to the untreated disks. Protein adsorption was significantly enhanced after 20 min of plasma treatment for 15 and 30 s on the MAC and SL disks. Plasma treatment for 15 and 30 s significantly increased the level of adhesion in both treated samples after 30 min. Furthermore, the MAC samples showed a significant increase in cell adhesion 4 h after plasma treatment for 15 s. The SEM analysis highlighted that, on the treated samples (especially on the MAC disks), the cells with a polygonal and flat shape prevailed, while the fusiform- and globular-shaped cells were rare. The encouraging results obtained further confirm the effectiveness of plasma treatments on cell adhesion and fibroblast activity.

Canullo, Luigi, et al. "Vacuum Plasma Treatment Device for Enhancing Fibroblast Activity on Machined and Rough Titanium Surfaces." Dentistry Journal 12.3 (2024): 71. 

Gas Plasma Treatment Improves Titanium Dental Implant Osseointegration—A Preclinical In Vivo Experimental Study 

Recent technological advancements led to the development of various plasma-based technologies for post-packaging modifications. The purpose of the present preclinical in vivo study was to assess the safety and efficacy of a novel chairside nonthermal gas plasma treatment for enhancing osseointegration of titanium implants. Six male mixed foxhounds underwent extraction of mandibular premolars and first molars, and the sockets healed for 42 days. Canine mandibles were randomized to receive either plasma-treated (test) or non-plasma-treated (control) dental implants. A total of 36 implants were placed in six animals, and they were sacrificed at 2 weeks (two animals), 4 weeks (two animals), and 6 weeks (two animals) after the implant surgery. When the radiographic analysis was performed, the changes in bone level were not statistically significant between the two groups at 2 weeks and 4 weeks. The difference became significant at 6 weeks (p = 0.016), indicating more bone loss from baseline to 6 weeks for the control group. The bone-to-implant contact (BIC) appeared to be higher for the test groups at all time points, and the BIC was significantly higher for the test group at 4 weeks (p = 0.046). In conclusion, this study underscored the potential of nonthermal plasma treatment in enhancing implant osseointegration.

▶ Statistical analysis demonstrating a significant difference in BIC between control and test implants at week 4.

Nevins, Myron, et al. "Gas Plasma Treatment Improves Titanium Dental Implant Osseointegration—A Preclinical In Vivo Experimental Study." Bioengineering 10.10 (2023): 1181.
 

Enhanced Osteoblast Adhesion and Proliferation on Vacuum Plasma-Treated Implant Surface 

In this study, we propose a vacuum plasma device for surface treatment of dental implants. This plasma device was designed to allow direct installation of sealed implant packaging containing the dental implant. In this manner, the dental implant could be treated with plasma under a moderate vacuum environment while remaining in a sterile condition. To assess the osseointegration efficiency, in vitro experiments using sandblasted, large grit, acid etching (SLA), calcium coated-SLA (CaSLA), and calcium coated-SLA with plasma treatment (PCaSLA) were performed. The implant surface was observed with scanning electron microscope (SEM) before and after plasma treatment. Thereafter, protein adsorption, cell adhesion, proliferation, and differentiation efficiency were investigated on the surface of each implant type using saos-2, an osteoblast. Plasma treatment significantly improved protein adsorption, cell adhesion, and cell proliferation efficiency compared to both CaSLA and SLA without damaging the calcium coating. According to the findings, the proposed vacuum plasma device has shown the potential to improve osseointegration efficiency. We believe that this plasma technology can be an innovative chairside solution that can be easily handled in the clinical field with superb usability.

▶ (A). SLA, (B). CaSLA, and (C). PCaSLA images after dipping the implants into a DW reservoir. Red dotted lines were drawn along the DW surfaces.

Jeon, Hyun Jeong, et al. "Enhanced Osteoblast Adhesion and Proliferation on Vacuum Plasma-Treated Implant Surface." Applied Sciences 12.19 (2022): 9884.

Improvement of osseointegration efficacy of titanium implant through plasma surface treatment

A novel plasma treatment source for generating cylindrical plasma on the surface of titanium dental implants is developed herein. Using the titanium implant as an electrode and the packaging wall as a dielectric barrier, a dielectric barrier discharge (DBD) plasma was generated, allowing the implant to remain sterile. Numerical and experimental investigations were conducted to determine the optimal discharge conditions for eliminating hydrocarbon impurities, which are known to degrade the bioactivity of the implant. XPS measurement confirmed that plasma treatment reduced the amount of carbon impurities on the implant surface by approximately 60%. Additionally, in vitro experiments demonstrated that the surface treatment significantly improved cell adhesion, proliferation, and differentiation. Collectively, we proposed a plasma treatment source for dental implants that successfully removes carbon impurities and facilitate the osseointegration of SLA implants.

Results of a XPS analysis, b protein adsorption, c cell proliferation, and d ALP activity for SLA and SLA + Plasma samples.
* P < 0.05, **P < 0.01, and *** P < 0.001 (Unpaired student’s t-test. Each SLA + Plasma data was compared to the corresponding SLA data.)

Forced convective heating for low-temperature sterilization 

A novel impermeable sterile pouch is developed to allow the forced convective heating mechanism for improving the sterilization cycle. The heating process is parametrically investigated to obtain an optimized condition in which a sterilization load is heated from 20 to 45℃ within 2 min, and the forced convection is experimentally and numerically analyzed to find that the convection coefficient is dramatically increased to 450 W/㎡ K when compared with the conventional natural convection coefficient of 80 W/㎡ K. The optimized heating process is applied to a sterilization cycle using the impermeable pouch, and the overall sterilization cycle is found to be completed within 7.5 min whose performance is validated by using a process challenge device.

▶ Heating mechanisms of the impermeable pouch.

▶ Operational parameters of pressure and temperature measured for the optimized sterilization cycle.

Lee, Seung Hun, et al. "Forced convective heating for low-temperature sterilization." Review of Scientific Instruments 92.6 (2021).